CYCS and holoprosencephaly: The cyclopic phenotype in tri mutants has been associated to deficiencies in shh signaling (Marlow et al., 1998) and since oep acts as a cofactor in TGFβ signaling (Gritsman et al., 1999) its cyclopic phenotype may have a similar origin to that observed in cyc. Although we cannot discount that these mechanisms partially underlie ethanol-induced cyclopia, our results suggest a different scenario.